Tooth.



L. E. EVSLIN TOOTH.

APPLICATION FILED MAY 2, 191 0 m w m M 5 w w 4 mm, 12 O 2 1 L UNITEDSIAIES PATENT OFFICE.

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State of New York, have invented cer- H new and useful Improvements in Teeth,

- 9' ,wln'ch the following is a specification.

. "$1111.15 invention has reference to artificial bneof the objects of the present inveni ,tion is to produce as an article of maina tooth, preferably of that kind ,wnes facings although the improvep'gnt applies equally as well to esthetic teeth,

such as are used to replace a full tooth and thevessential improvement is to provide the tooth labial face of such tooth. S

' incisal edge of the too with a groove leading in from the cervical border and opening out of its posterior face, and wherein the basal or inner wall of ,the groove diverges from the cerviGfll border toward the bit edge and the 351 construction produei a groove wherein its basal or inner we is spaced farther from the posterior face ator near the biting edge of the tooth than at the cervical border, which rind and bevel, the

tra n the posterior :Eace, whereby its backing may be burnished over such bevel portion so as to rotect the biting'edge of the tooth and tereby the patient will bite on metal instead of altogether on porcelain, and when once adjusted interchangeability will not be destroyed because of. the shape of the groove permitting the tooth to be easily removed from its backing and tongue employed to connect the tooth to the backing.

In the accompanying drawings: Figure 1 is a vertical sectional view of a tooth, the tongue being omitted and the incisal or hiting edge of the tooth ground or beveled from the posterior face, and Fig. 2 is a View similar to Fig. 1, except that the tongue and backing have been attached to the tooth and the backing has been burnished over the beveled portion of the tooth at the biting edge so as to produce a self-protecting metallic edge. .7 The view also further shows in dotted lines the angle of the basal wall of the groove.

In the drawings, 16 designates a tooth of the kind called facing, having the incisal or cutting edge 17, a posterior surface 18, a labial surface-19 and a cervical Specification of Letters imam. Mamas no; an a, mo. Serial no. staaer.

- I' all whom it may cortcem:

Patented Dec. 15, 1914.

border 20. Such tooth is provided with a a groove 21, preferably dovetail in cross section, having a rear flat wall 22, known as the basal wall, and converging side Walls 23. This groove commences at the cervical border 20 of the posterior surface and runs toward the cutting edge of the tooth. The

groove 21 opens at the posterior surface of' the tooth and stops short of its cutting edge approximately one third of the length of sa1d tooth, said groove, however, continuing 1ns1de in the direction of the extreme tip of the tooth and terminatin a reasonable distance from the tip of t e tooth to allow for such modification in the tip of the tooth as may be desired in its use. The end wall of the groove 21 in the tip of the tooth is beveled, as shown at 24.

A metallic lining or boxing 25, is preferably baked in the tooth at the time the tooth is molded.

The basal or inner wall 22 of the groove ex tends, obliquely into the tooth, or in other words diverges from the cervical border toward the tip of the tooth, "whereby the depth of the groove from the posterior surface 18 to the basal wall 22 is of greater depth at or near the tip portion of the tooth than at or near the cervical border of thev Blam 8 1s a tongue. This tongue has an elonf tpted body portion, preferably wedge shaped and with beveled ends 29, one of whlch corresponds to the bevel wall 24 in the tooth, while the back and side walls of said tongue correspond to the shape of the groove and boxing of the tooth, so as to have a slidable relation therewith, being inserted into such groove at the cervical border. This tongue has a flared or wing extension 30, projecting from the 'narrow edge of the tongue, and in this instance it is disposed near one end thereof. The tongues are preferably made in difl'erent len he to suit the various lengths of teeth and in each case the placing of the flared or wing extension is such that when attached to a tooth it is approximately central of the tooth for attachment to the backing. The beveled sides of the tongue and the side faces of the flared or wing extensions are milled or serrated as at 31 to provide adhering surfaces for the cement, and especially are the expreliminary attaching and shaping of the backing to the tooth the hard1wax applied to secure the extension to the backing, will more readily adhere to the extension and thereby the tongue and backing be more readily removed preparatory to securing the backing to crowns, abutments, bridges, etc.

The arrangement of the moves in the teeth, as described, with the %8.S8,l wall disposed obliquely, permits the practitioner to grind and shape the biting edge of the teeth at an angle as at 32, when a protecting tip of metal is desirable. The advantage of the basal wall being at an angle, as described, rather than being parallel with the posterior surface is, that the cutting edge of the tooth may be shaped or ground to any desired thinness or angle without destroying the interchangeability of the tooth, for the reason that teeth cannot be manufactured with the cutting edges thin enough for ractical pun poses, because their edges wil burn away during the last firing of the porcelain of the tooth.

Heretofore in interchangeable teeth where the basal wallof the groove or the groove itself was parallel with its posterior surface, when the backin was applied, if it became necessary to re uce the cutting edge of the tooth, in manner explained, and shape the backing to it, the backing would become locked on the tooth and thus all interchangeability destroyed, and to obviate this it has been the custom to grind down and shape the labial face of the tooth at the biting edge and in doing this the surface becomes pithy and loses its translucency, while with my invention this is overcome in a most natural way by grinding the cutting edge at its pos terior face.

In constructing interchangeable artificial teeth particularly anterior teeth, the tooth commencing from its middle part at the posterior surface and ending at the cutting edge, must be produced as thin as the labial surface of the tooth will ermit. Producing a tooth in accordance with the improvements herein outlined, I overcome and obviate the extra thickness so common both in anterior and short teeth, which renders a tooth practically useless, for the reason, that in a great many cases, the superior anterior teeth are found to overlap those of the inferior anterior teeth. In such cases, the bite is very close and the inferior anterior teeth strike about the middle part of the superior anterior teeth, therefore the necessary space must be provided.

What I claim is In combination, a tooth having a groove and with the bite bevel at the posterior surface to provide for a protecting tip of metal, the basal wall of the groove having an oblique position in the tooth relative to the posterior surface thereof, a tongue for the groove, said tongue having an extension member, a backing, said backing conforming to the posterior surface of the tooth, and recessed to receive the extension member of said tongue.

In testimony whereof I afiix my signature, in presence of two witnesses.

LEO E. EVSLIN.

Witnesses:

Geoaon OFFIN, ROBERT Pnown.

teeth, as described, with the preliminary attaching and shaping of the ackmg to the tooth the hard-wax applied to secure the extension to the backing, will more readily adhere to the extension and thereby the tongue and backing be more readily removed preparatory to securing the backing to crowns, abutments, bridges, etc.

The arrangement of the rooves in the as al wall disposed obliquely, permits the practitioner to grind and shape the biting edge of the teeth at an angle as at 32, when a protecting tip of metal is desirable. The advantage of the basal wall being at an angle, as described, rather than bein parallel with the posterior surface is, that t e cutting edge of the tooth may be shaped or ground to any desired thinness or angle without destroying the in.- terchangeability of the tooth, for the reason that teeth cannot be manufactured with the cutting edges thin enough for ractical purses, because their edges will burn away uring the last firing of the porcelain of the tooth.

Heretofore in interchangeable teeth where the basal wallof the groove or the groove itself was parallel with its posterior surface, when the backin was applied, if it became necessary to re uee the cutting edge of the tooth, in manner explained,-and shape the backing to it, the backing would become locked on the tooth and thus all interchangeability destroyed, and to obviate this it has been the custom to grind down and shape the labialface of the tooth at the biting edge and in doing this the surface becomes pithy and loses its translucency, while with my invention this is overcome in a most natural [Sean] way by grinding the cutting edge at its p'os, tenor face.

In constructing interchangeable artificial teeth particularly anterior teeth, the, tooth commencing from its middle part at the posterior surface and ending at the cutting edge, must be produced as thin as the labial surface of the tooth will lpermit. Producing a tooth in accordancewit the improvements herein outlined, I overcome and obviate the extra thickness so common both in anterior and short teeth, which renders a tooth practically useless, for the reason, that in a great many cases, the superior anterior teeth are found to overlap those of the inferior anterior teeth. In such cases, the bite is very close and the inferior anterior teeth strike about the middle part of the superior anterior teeth, thereforethenecessary space must be provided.

What I claim is- In combination, a tooth having a groove and with the bite bevel at the posterior surface to provide for a protecting tip of metal, the basal wall of the groove having an oblique position in the tooth relative to the posterior surface thereof, a tongue 1914, upon the application of Leo E. Evslin, of New York, N Y., for improvement in Teeth, an error appears in the printed specification requiring correction as follows: Page 2, line 61, for the word bevel read bearded; and that the said Letters Patent should be read with this correction therein that the same may conform to the'record of the case in the Patent Oflice.

Signedand sealed this 19th day of January, A. D., 1915.

R. F. Wl'Il'lEl-IEAD,

Acting Commissioner of Patents.

It is hereby certified that in Letters Patent No. 1,120,704, granted December 15,

It is hereby certified that in Letters Patent No. 1,120,704, granted December 15,

1914, upon the application of Leo E. Evslin, of New York, N. Y., for :11 improvement in 'Ieeth," an error appears in the printed specification requiring correction as follows: Page 2, line 61, for the word bevel read bare/ed; and that, the

said Letters Patent should be read with this correction therein that the same may conform to the record of the ease in the Patent Office.

Signed and sealed this 19th day of January, A. D., 1915.

[SEAL] R. F. W'Ill'lEl-IEAD,

Acting Commissioner of Patents. 

